a) Field of the Invention
The present invention relates to an indexable cutting insert, an insert seat for an indexable cutting insert and a cutting tool having an insert seat and an indexable cutting insert.
b) Description of the Related Art
Such indexable cutting inserts can be of one-sided or double-sided design. In a one-sided indexable cutting insert, as is known, for example, from WO 2007/127109 A1, a main face of the indexable cutting insert is configured as a working surface. The working surface has a plurality of cutting edges at its rim. If the effective cutting edge has become worn after a predetermined number of machining operations, the cutting insert is rotated in the insert seat, such that the next lip is used. Such indexable cutting inserts can be designed to be, for example, triangular, square or hexagonal and then correspondingly have three, four or six lips, which are used one after the other.
As a further embodiment, double-sided indexable cutting inserts are known, for example from WO 2007/037733 A1. In these indexable cutting inserts, both insert surfaces are designed as working surfaces and each have cutting edges at their rims. During the machining, first of all the one working surface forms the active machining surface, while the surface facing away from this machining surface is inactive and rests on the supporting surface of the insert seat. First of all, in these indexable cutting inserts, the cutting edges of the active machining surface become worn one after the other as in a one-sided indexable cutting insert. If the lips of the active machining surface have become worn, the indexable cutting insert is rotated by 180° in the insert seat, such that the worn machining surface rests on the supporting surface and the inactive surface resting previously on the supporting surface becomes the active machining surface. The cutting edges of this active machining surface also become worn one after the other.
Finally, a further double-sided indexable cutting insert is known from WO 2007/104275 A1. This cutting insert has a lip rim having a positive rake angle, said lip rim adjoining the cutting edge. Adjoining the lip rim is a falling surface which extends conically about the central through-hole. The advantage of this indexable cutting insert lies in the fact that inaccuracies when tightening the fastening bolt can be compensated for by the conical region.
With such double-sided indexable cutting inserts there is the problem of configuring the insert seat in such a way that the indexable cutting insert rests securely and fixedly in the insert seat and can be securely clamped there, but without damaging the cutting edges facing the supporting surface or those regions of the inactive working surface of the indexable cutting insert which are near the lip, said working surface facing the supporting surface of the insert seat. In particular, it is desirable to be as free as possible with regard to the configuration of the geometry of the cutting edges and of the chip breakers.
The object of the present invention is therefore to design an indexable cutting insert which can be positioned and clamped in the insert seat in an effective and dimensionally accurate manner and whose lip geometry and whose regions near the lip can be designed as freely as possible and so as to be adapted to the respective application.